Chaser grinding means



Nov. 16, 1937. c. s. MUELLER CHASER GRINDING MEANS Filed Nov. 29, 1955 wen/67M WWW Patented Nov. 16, 1937 UNITED STATES PATENT OFFECE 8 Claims.

10 is adjustable to hold a chaser in various desired positions for grinding, and is easily operable to effect an efficient grinding movement of the chaser with respect to the grinding wheel and to exert a desired pressure of the chaser against the grinding wheel.

The invention is fully described in the following specification, and one embodiment thereof illustrated in the accompanying drawing, in which- Figure 1 is a perspective view of a grinding unit with a chaser holder embodying the invention associated therewith and in operative grinding position; Fig. 2 is an elevation thereof looking toward the edge of the grinding wheel and with {25 the grinding unit fragmentarily shown; Fig. 3 is a plan view of the chaser holding means in operative relation to a grinding wheel, which is fragmentarily shown; Fig, 4 is an enlarged fragmentary face View of the adjustable chaser car- 30 rying head of the device with a chaser clamped in position thereon, and Fig. 5 is an enlarged section on the line 5-5 in Fig. 3.

Referring to the drawing, I designates a motor having a base2 and provided on an extended 6m of its shaft with a grinding wheel 3. The chaser holding unit embodying the invention includes a bracket 4 which projects horizontally from the base 2 in advance of the grinding wheel 3, and, in the present instance, has its inner end 1:40 fitting a corner of the base and secured thereto by screws 5, while at its outer end it is provided with a depending flange 6 forming a foot for supporting the outer end of the bracket.

The bracket 4 at its outer end is provided with 'a slot 1 disposed transverse to the grinding wheel axis and adapted to receive a bolt 8, which also passes through a longitudinally extending slot in a cross-arm 9, whereby such arm is adjustably connected to the bracket 4. It is thus apparent that the cross-arm 9 is capable of rotary adjustment relative to the bracket 4, as well as adjustment transverse to the bolt 8 and adjustment with the bolt lengthwise of the slot 1.

i The ends of the cross-arm 9 are disposed at opposite sides of a plane common to the diametrical plane of the grinding wheel 3, and posts I and I I rise from opposite ends of the cross-arm. The former may be termed a pivot post and the latter a stop post for the chaser carrying parts of the device.

A frame I2 is mounted at one end for free horizontal swinging and vertical sliding movements on the post I0, being provided for such purpose at one end with vertically spaced bearing bosses I3. The frame I2, at the end thereof opposed to the post I0, is provided with a web extension I4, which is adapted to abut against the outer side of the post I I and thus limit the inward swinging movements of the frame with respect to the grinding wheel. The body portion of the framel 2 is broadened in a direction outwardly from the vertical plane of the posts I0 and II and forms a bearing for a shaft I5, which is provided at its inner end, with respect to the grinding wheel, with a chaser carrying holder I6. The Y shaft I5 is intermediate the posts Ill and II with its axis transverse to the grinding wheel axis, and

it is mounted to have axial adjustment in the frame I2 in a plane substantially at right angles to the plane of movement of the frame lengthwise of the posts I0 and II. The shaft is prevented from having rotary movements in the frame, and for. such purpose, in the present in- .stance, is provided on one side with a longitudinally extending flat I1 with which a screw con- .trolled tapered key I8 in the head is adapted to coact. This permits wear to be taken up and .prevents any rocking of the shaft relative to the frame. A feed nut I9 is threaded on the shaft I5 within a notch or opening 20 in the frame, and .is adapted, when turned, to impart axial movement in one direction or the other to the shaft. This nut has a portion of its periphery preferably knurled and is quite broad to facilitate hand adjustment by the operator, and is also provided ,around one edge portion with a graduated scale which registers with a point on the frame to indicate the extent of turning.

Thechaser holder I 6 at one end has a split bearing part 2I which receives an end of the shaft 5 I5 and is clamped thereto by means of a screw 22.

,The opposite end of the holder I6 projects a distance from the shaft transversely of the diametrical plane of the grinding wheel 3, and is provided'on the side thereof adjacent to the wheel with an L-shaped seat 23 for receiving and supporting a chaser 24 to be ground. The chaser is -adapted to seat at its lower edge on the bottom ledge portion of the seat and to have its rear side abutflatwise against the upright portion of the 55 seat, as shown. The chaser is firmly held in adjusted postion to the seat by a clamping screw 25, which is threaded in the upper portion of the holder, and is provided with a collar 26 for clamping engagement with the upper edge of the chaser in opposition to the base ledge of the seat 23. The chaser, when clamped in grinding position on the holder, has the edge thereof to be sharpened facing the grinding edge of the wheel 3 and disposed in a plane tangential to the wheel. The chaser is also mounted on the holder, so that its cutting end is adjacent to the shaft I5, as shown in Figs. 1 and 3.

For convenience of reference, the cross-arm 9 and posts It and il may be termed the guide frame, the frame I2 may be termed the control frame and the head It and its shaft I5 may be termed the chaser holder.

In the operation of the device, a chaser to be sharpened is mounted on the holder seat 23 and spaced in pro-per grinding relation to the grinding wheel edge by an adjustment of the guide frame 9, It, II with respect to the bracket 4 and also an adjustment of the holder shaft I5, which latter is accomplished by a turning of the nut I9. This adjustment should be such that when the frame i2 is in stop coaction with the post II, the edge of the chaser to be ground registers with the adjacent edge of the grinding wheel and can be moved freely up and down with the frame tangentially of and in close proximity to, but not striking the edge of the wheel, and in a plane which is parallel to the diametric plane of the wheel. The proper position of the chaser with'respect to the grindingwheel having thusv been obtained, the nut I9 may be turned to feed the holder forward into grinding engagement with the wheel. During such grinding, the frame i2 is reciprocated on the post I!) and against the post I I, so as to cause the elongated cutting edge of the chaser to tangentially traverse the coacting grinding edge of the wheel a suflicient number of times to effectively sharpen the chaser.

During the grinding operation, the post II not only serves to guide the vertical reciprocatory movements of the frame I 2, but limits the inward movement of the chaser with respect to'the work, except when a feeding movement is being applied to the shaft l5, thus enabling the operator to press'the chaser against the wheel Without danger of taking off too great a cut or of injury to the chaser edge being sharpened. It is apparent that as the grinding progresses, the chaser may be advanced to the wheel by a turning of the nut I9 as the grinding operation may require.

If the chaser being ground is of the type for cutting a straight thread, the holder I6 is set so that the bottom edge of the chaser is in a plane parallel to the grinding wheel axis, and if the chaser is of a type adapted for cutting a tapered thread, the holder is tilted on the shaft I relative to such parallel position an extent necessary to suit the taper of the cutting edge of the chaser. The clamping screw 22 may be loosened to permit such adjustment.

It is found that the initial adjustment of the chaser with respect to. the wheel may be facilitated by clamping the frame I2 to the guide post Ii! with the chaser in the position with respect to the wheel substantially as shown in Fig. 1. For this purpose, the post I0 is encircled between the bearing boss I3 by a split collar 30 which coacts at top and bottom withthe respective bosses and is provided with a clamping screw 3|, which is operable to clamp or release the collar with respect to the post. The clamping collar 30 and its screw 3 I, when in clamped relation to the post I0, are adapted to abut against the body of the control frame I2 and hold it in engagement with the post II.

I wish it understood that my invention is not limited to any specific construction, arrangement or form of the parts, as it is capable of numerous modifications and changes without departing from the spirit of the claims.

Having thus described my invention, what I claim as new, and desire to secure by United States Letters Patent, is:

1. A grinding fixture for thread cutting chasers having a' U-shaped guide with post-like legs, means mounting the guide for various adjustments, a control frame mounted on one of said legs for free linear reciprocatory and rocking movements in different angularly disposed planes and for stop coaction with the other leg, a chaser holder carried by the control frame for feeding movements relative thereto in one of the planes of permissible movement thereof, and means operable to impart predetermined feeding movements to the chaser holder. 7

2. A grinding fixturefor thread cutting chasers having a guide with two guide posts, a control frame mounted on one post for free reciprocatory movements lengthwise thereof and swinging movements transverse thereto toward and away from the other post, a chaser holder carried by the control frame for feeding adjustment in the plane of swinging movements thereof, and means operable to impart feeding movements to said chaser holder. 7

3. The combination with a grinding wheel, of a vertical guide, means mounting said guide for "various adjustments in a horizontal plane, a control frame guided for free vertical reciprocatory movements by the guide: in a plane tangential to the adjacent wheel edge, said 'control'frame also being mounted for horizontal swinging movements relative to the guide toward and away from the Wheel periphery in a direction generally radially of its axis, a chaser holder carried by the control frame for engagement with the adjacent edge of the wheel and for adjustment in the control frame toward and away from the wheel, and means for imparting adjusting movements to said chaser holder relative to the control frame.

4. The combination with a grinding wheel, of a vertical guide, means mounting said guide for various adjustments in a horizontal plane, a control frame guided for free vertical reciprocatory movements by the guide in a plane tangential to Y the adjacent wheel edge, said control frame also being mounted for horizontal swinging movements relative to the guide toward and away from the wheel periphery in a direction generally radially of its axis, a chaser holder carried by the control frame for engagement with the adjacent edge of the wheel and for adjustment in the control frame toward and away from the wheel, means for imparting adjusting movements to said chaser holder relative to the control frame, and means for limiting the swinging movements of the control frame toward the wheel at any position of vertical movement of the frame on the guide.

5. The combination with a grinding wheel, of a Vertical guide post and a stop post, a control frame spaced from the edge of the wheel radially thereof and mounted on said guide post for free vertical reciprocatory movements in a plane tangential to the adjacent wheel edge, said frame also adapted for horizontal swinging movements on the guide post toward and away from the adjacent wheel edge and the stop post in a general direction radially of the wheel axis, a chaser holder carried by the frame for adjusting movements relative thereto toward and away from the adjacent wheel edge, said holder having a chaser carrying part which is tiltingly adjustable relative to the control frame in a plane tangential to the wheel, and means for locking said frame in any position of its vertical movement on the post.

6. The combination with a grinding wheel, of a stationary bracket, a U-shaped guide frame mounted on the bracket for various horizontal adjusting movements and having its legs projecting vertically in a plane tangential to the wheel edge, a control frame mounted on one of said legs for free vertical reciprocatory movements and for horizontal swinging movements relative thereto toward and away from the adjacent wheel edge, the other leg of said guide frame serving as a stop in any position of vertical movement of the control frame to limit its inward swinging movements toward the wheel edge, a chaser holder carried by the control frame for adjusting movements toward and away from the adjacent wheel edge in a plane at an angle to said tangential plane, and means for imparting adjusting movements to said holder.

7. The combination with a grinding wheel of a guide frame disposed adjacent to an edge of said wheel and having laterally spaced parts, a control frame carried by one of said parts for free reciprocatory movements in a plane tangential to the adjacent wheel edge and for swinging movements in a horizontal plane toward and away from the wheel edge, said other guide frame part serving as a combined guide and stop respectively for said movements, and a chaser holder carried by the control frame for adjusting movements in a horizontal plane toward and away from the adjacent wheel edge.

8. A grinding fixture for thread cutting chasers having a guide frame with a guide post and a stop post, a control frame mounted on the guide post for free reciprocatory movements lengthwise thereof and for coaction during such movements with the stop post and for swinging movements toward and away from the stop post, said transverse movements being limited in one direction by the stop post in any position of lengthwise reciprocatory movements of the control frame, a chaser holder carried by the control frame for reciprocatory feeding movements relative thereto in a plane which is angularly disposed with respect to the said lengthwise movement of the control frame.

CLARENCE S. MUELLER. 

